constant-expression

C++ expected constant expression

#include <iostream> #include <fstream> #include <cmath> #include <math.h> #include <iomanip> using std::ifstream; using namespace std; int main (void) { int count=0; float sum=0; float maximum=-1000000; float sumOfX; float sumOfY; int size; int negativeY=0; int positiveX=0; int negativeX=0; ifstream points; //the points to be imported ...

Creating array with constant

I was working on a program in Netbeans on Linux using a gcc compiler when, upon switching to Visual C++ on Windows 7, the code failed to compile as Visual C++ says it expected constant expression on several lines. On Netbeans, I simply did something similar to char name[fullName.size()];, while on Visual C++, I tried, among other things,...

Constant expression with custom object

I'm trying to use an instant of a custom class as a template parameter. class X { public: X() {}; }; template <class Foo, Foo foo> struct Bar { }; const X x; Bar<X, x> foo; The compiler states that x cannot appear in a constant expression. Why that? There is everything given to construct that object at compile time. ...

Can i have a negative value as constant expression in Scala?

I have an Java-Annotation that return a double value: @Retention(RetentionPolicy.RUNTIME) @Target(ElementType.FIELD) public @interface DoubleValue { double value(); } When i try to attach the annotation to a field in a scala class and the value is negativ like here: class Test { @DoubleValue(-0.05) var a = _ } i get an compi...

Example of Something Which Is, and Is Not, a Constant Expression in C?

I'm a tad confused between what is and is not a Constant Expression in C, even after much Googleing. Could you provide an example of something which is, and which is not, a Constant Expression in C? ...